#include <iostream>
using namespace std;

void swap(int &x, int &y)
{
    int temp;
    temp = x;
    x = y;
    y = temp;
    return;
}

int main()
{
    int a = 100, b = 200;
    cout << a << b << endl;

    swap(a, b);
    cout << a << b << endl;

    return 0;
}